Oxymetazoline and its use for the treatment of skin diseases and disorders, including rosacea, is described in U.S. Pat. Nos. 7,812,049 and 8,883,838, the entireties of which are hereby incorporated by reference. Oxymetazoline is an alpha-2 adrenergic agonist currently being investigated for the treatment of the erythematosus component of rosacea. Due to the high ionic strength of the formulation imparted by the presence of oxymetazoline, creating a stable, efficacious, and cosmetically elegant formulation is difficult.
Rosacea is a chronic disease most commonly characterized by facial erythema (redness). There are at least four identified rosacea subtypes and patients may have more than one subtype present. The four most well recognized subtypes are erythematotelangiectatic rosacea (ETR); papulopustular rosacea; phymatous rosacea; and ocular rosacea. Other less common forms exist and the signs and symptoms of each subtype are not unique to that subtype and may overlap or coexist with any of the manifestations of any other subtype. ETR may be characterized by transient and/or permanent erythema with a tendency to flush and blush easily and telangiectasias, which in its milder form may resemble or present as erythema (redness) and in its more pronounced state may manifest as discrete visible blood vessels on the surface of the skin. Papulopustular rosacea may be characterized by transient and/or permanent erythema with papules (red bumps) and pustules (pus filled bumps). Without wishing to be bound by theory, though the papules and other inflammatory lesions (e.g. pustules) of papulopustular rosacea may be mistaken for acne, it is believed that the papules and pustules of rosacea are different from the papules and pustules of acne and arise from different underlying pathophysiologic processes. Phymatous rosacea may be characterized by thickening skin, irregular surface nodularities, enlargement of facial areas (e.g. nose and cheeks), erythema and telangiectasias. Ocular rosacea may be characterized by red, dry and irritated eyes and eyelids. In each subtype, erythema and telangiectasias of varying degree may be a feature.
Rosacea patients may need topical or oral (systemic) medication to alleviate their distress; however, a patient's skin may be so sensitive that many products are irritating and, in fact, may exacerbate the symptoms of rosacea and may cause more redness and discomfort than patients can tolerate. Thus, rosacea can be very difficult to effectively treat and thus may not only be physically distressing but also psychologically distressing. Accordingly, there is a need for a cosmetically and pharmaceutically acceptable therapeutic which addresses the myriad manifestations of rosacea including, but not limited to, the erythema or redness associated with rosacea and the telangiectasias associated with rosacea. Additionally, there is a need for a cosmetically and pharmaceutically acceptable therapeutic which addresses the inflammatory lesions and manifestations associated with rosacea including the papules, pustules and phymas (skin thickening).
There exists a need for improved stabilized cream formulations of oxymetazoline that are effective and well tolerated after topical administration to human patients.